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be seen, only when they have reached a rather considerable 
size, the stony coat begins to differentiate, and herewith 
the ribbing occurs. The first indication of it is to be seen 
on transverse sections at the micropyle. In a young stage 
this is entirely round, but when the ovule has attained a 
diameter of about half a centimeter, it looks like a long 
stretched fissure or ike a triangle with collapsed sides 
(fig. 5). Sections made lowerdown, show clearly the 
places of the ribs. 
In sections close below the micropyle, at the places of 
the ribs, an elongation of the cells is to be seen as a 
Fig. 6. Ginkgo biloba, transverse section below the micropyle, on 
the place of the rib; an elongation of the cells is to be seen. 
lengthening of the fissure, giving the impression of 
a suture (fig. 6). 
À resarch has been made by Affourtit and La 
Rivière concerning the ribbing of the seeds (1). The 
irregularity of those ribs has struck them and they made 
a statistic of their occurrence with the help of a great 
number of seeds, originating from the same tree from 
which my material was collected. Trom the 117 examined 
